The 2015 model is longer and wider, but weighs 200 pounds less due to a partly aluminum body, which also offered more freedom when it came to curves and detailing. "It's about the materials you don't see, but you feel and hear through different senses—that's how we design," he says.

Wagener pushed the cabin back, lengthening the hood and shifting the focus of the car to the rear. He also tapered the cabin and raised the back for a classic "dropping line" stance. "We took inspiration from 1930s streamlined design," he says. As a result, the C-Class is unusually aerodynamic.